Elevator-control system



A. A. GAZDA.

ELEVATOR CONTROL SYSTEM.

APPLICATION FILED JAN-5,1918- 1,390,526. PatentedSept. 13, 1921.

4. 8 /a l za 'fy/ WITNESSES:

INVENTOR Ada/ 0M Gqzda UNITED STATES PATENT OFFICE.

ADOLPE A. GAZDA, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE -ELEOTRIC AND MANUFACTURING COMPANY, CORPORATION PENNSYLVANIA.

ELEVATOR-CONTROL SYSTEM.

. To alt whom it may concern:

Be it known that I, 'AnoLPH A. GAZDA, a

citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Elevator-' Control Systems, of which the following is a specification.

My invention relates to control systems and particularly to control systems for accelerating electric motors and 'for bringing the same-to rest by dynamic braking.

My invention is particularly applicable to elevators, hoists and similar machines.

In present commercial arrangements, the

"brake coil is operated through relays controlled by a mechanism which controls also the contact members of the main switches. It is an object of my invention to dispense with thesev relays and to so simplify the connections that the mere opening of the main contact members directly releases the brake.-

Another object of my invention is to make use of the starting resistor in dynamic braking, thereby limiting the braking current which flows through the dynamic-brakin resistor.

IDuring the acceleration or the deceleration of a motor, as successive increments of the resistor are removed from, or inserted into, the armature circuit, the motor is subjected to sudden rushes of current. In the case of an elevator, for example, the eflect is to cause the elevator to move by jerks and jumps. One of the objects of my invention is to reduce this eflect to a minimum.

' Other objects of my invention will be apparent from the following descript' 11 when taken iii-connection with the accom anying drawings.

In the drawings, Figure'l is a diagram- The motor may be operatively connected, ,for

example, to an elevator car. The direction of rotation of the motor is controlled by re- Specification of Letters Patent.

Application filed January 5, 1918. Serial No. 210,580.

Patented Sept. 13, 1921.

versing switches 5, 6, 7 and 8, the switches 5, 7 and 9 being mechanically connected, as are also the switches 6, 8 and 10. The

switches 9 and 10 connect the braking resistor 20,.hereinafter referred to, in a dynamic-braking circuit when the reversing switches are open.

A sectional starting resistor 11, which is in series with the armature 3, is controlled by a series of electromagnetic switches 12,

13 and 14;. An induction coil 16 is connected in the motor circuit between the armature 3 and the resistor 11, and following the shuntin'gof the resistor 11, is shunted by switch 15. A resistor 17 which is in parallel with the motor armature and the induction coil, is controlled by a plurality of electromagnetic switches indicated at 18 and 19. .By this arrangement, the reversing switches do not break any induction circuits.

In the circuit of the field winding 4 may be inserted shunt or series resistors, or both, and the field winding may, if desired, be

composed of two parts, astanding field and an extra field. A dynamic braking resistor, as shown at 20, is connected in parallel circuit with the armature 3 and the resistor 11 between the switches 6 and 8 or 5 and 7, re-

spectively. A brake coil 21 is connected, at one end, to one end of the resistor 20 and, at the other end, to the line. The brake coil 21 may be provided with resistors in series and in shunt, which resistors, for the sake of simplicity, have been omitted from the drawing. The electromagnetic switches 12 to 15 may be actuated by a series of coils which are controlled by auxiliary switches, the coils of which may be inserted in the armature circuit between the induction coil and the resistor 11. The usual emergency and limit switches have been omitted from the drawings, as they form no part of the present invention. One limit switch, for example, may be located at 22.

It will be noted that, by connecting the brake coil 21, at one end, to thedynamicbraking resistance, and, at the other end, to the line, I am enabled to operate the coil 21 independently of the relays customarily employed, by the mere opening or closing of switches 6 and 8,. and 5 and 7, respectively. If desired, however, for safetys.

switches may also braking resistor 20. By thus connecting the resistor 11 between the reversing switches, I am enabled to make use of it in the dynamic-braking circuit.

Fig. 3 illustrates the connections when the controller (not illustrated) is moved to its first position, thereby closing the switches 6 and 8 and opening switch 10.x

The braking resistor has been omitted from Figs. 3 to 6 for one 'of the switches 9 and 10, in the schematic views illustrated by the figures, is always open. The eifect is to send current, from the line conductor 1 through armature 3, induction'coil 16 and resistor 11 'to the other line conductor 2. At the same time, a shunt circuit is established through a portion of the resistor 17 around th armature 3 and the induction coil 16, and a second shunt circuit is made through the brake coil 21. The brake coil being thus energized, the brake is released. Owing. to the presence of induction coil 16, the rate of change of current in the armature circuit is diminished andthe rise or fall of current itself made more gradual. The next step is to insert,'in one or more operations, the whole resistor 17, as is illustrated in Fig. 4. Fig. 5 represents the next operation, which consists in removing from the circuit the resistor 17. The resistor 11 and induction coil 16 are then gradually shunted, as shown in Fig. 6. Reslstance is then inserted in the circuit of shunt fieldmagnet winding 4, causing. the" motor to be accelerated.

In decelerating, the operation corresponds, in every material res ect, to that described in connection with igs. 2 to 6, but in the reverse order.

The reversing switches 5 and 7 operate to reverse the connections of the motor armature 3, and the several switches for controlling the resistors operate in the same manner as that already described. The decreaseof resistance in the shunt field circuit, and the insertion of resistance in the armature circuit cause correspondingly decreased speed of the motor, and, finally, with the openin of the reversing switches 5 and 7, the ynamic-braking circuit of Fig. 2 becomes reestablished.

I claim as my invention:

1. In a control system, a motor circuit including a source of power, a dynamic-brake resistor, and a brake coil permanently connected, at one end, to said resistor and, at the other end, to said source of power.

2. The combination with a source of energy, an electric motor having a starting resistor and a dynamic-braking resistor,

and means for connecting said motor to said source, of means for connecting the armature of said motor in circuit with both said resistors upon said connecting means becoming inoperative.

3. In a motor-control system, the combination with a source of power, an armature winding, and an induction coil and a starting resistor in series therewith, of a dynamic-braking resistor in parallel relation with said armature, said induction coil and said starting resistor, and a brake coil connected, at one end, to said dynamic braking resistor, and, at the other end, to said source of power.

4. The combination with a source of power and a motor having an armature, of a dynamic-braking resistor in parallel relation with said armature, and a brake coil connected, at one end, to said dynamicbraking resistor, and, at the other end, to said source of power.

5. An electric circuit including an armature, an induction coil in series therewith,

and a"'res1stor in parallel circuit with said armature and said coil.

6. In a control system, a pair of switches, an armature and an induction coil between said switches, and a resistor in arallel circuit with said armature and sai coil.

In testimony whereof, I have hereunto subscribed my name this 21st day of Dec.

ADOLPH A. GAZDA. 

